Carrier 53QG18-H Installation Manual

34Unit onCoolingWait about3 minutes3312CONNECTING REFRIGERANT PIPING LINES (Cont.)15-13 REFRIGERANT LEAK CHECKAfter connecting the refrigerant piping lines, with bothoutdoor and indoor units check the joints for leakage withelectronic leak detector or soapy water.15-14 INSULATING REFRIGERANT PIPING LINESTo conserve energy and prevent wet floors due tocondensation, the suction and liquid piping lines must be wellinsulated with a proper insulation material.The thickness of the insulation should be a minimum of 9 mm.The insulation you select must have good insulationcharacteristic, be easy to use, resist age and not easily absorbmoisture.Finally wrap the flare couplings and pipes with insulation andtighten this with tape without exerting too much pressure onthe insulation.CAUTION:• After a pipe has been insulated, never try to bend it into anarrow curve, as this way will cause the pipe to break orcrack.• Repair and cover any possible cracks in the insulation• Avoid dripping due to insufficient insulation of piping.15-15 PUMP DOWNPump down means collecting all the refrigerant in the systemback into the outdoor unit. Pump down must be actuatedbefore disconnection of pipes, to avoid loss of refrigerant gas.Pump down is used when the unit is moved to anotherinstallation location or when the system is repaired.PUMP DOWN PROCEDURE :1. Close the liquid valve with the Allen wrench.2. Turn the system ON in cooling mode with fanoperating at high speed.Then the refrigerant will be collected into the outdoor unit.(Compressor will immediately start, provided 3minutes have elapsed since the last stop).3- After 3 minutes of operation, close the suction valvewith the Allen wrench.Turn the system off and switch mains supply OFF.Disconnect refrigerant piping lines.After disconnection, protect valves and piping endsfrom dust.PipeInsulationPipeFastening tape